Mat base



FIG. 1 is a bottom plan view of a mat base in accordance with a first embodiment;

FIG. 2 is an oblique bottom view of the mat base of FIG. 1;

FIG. 3 is a detail of the view of FIG. 2;

FIG. 4 is a bottom plan view of a mat base in accordance with a second embodiment;

FIG. 5 is an oblique bottom view of the mat base of FIG. 4;

FIG. 6 is a detail of the view of FIG. 5;

FIG. 7 is a bottom plan view of a mat base in accordance with a third embodiment;

FIG. 8 is an oblique bottom view of the mat base of FIG. 7;

FIG. 9 is a detail of the view of FIG. 8;

FIG. 10 is a bottom plan view of a mat base in accordance with a fourth embodiment;

FIG. 11 is an oblique bottom view of the mat base of FIG. 10; and,

FIG. 12 is a detail of the view of FIG. 11.

The broken lines depict portions of the mat base that form no part of the claim. 

CLAIM The ornamental design for a mat base, as shown and described. 